This application claims the benefit of Korean Application No. 00-9623, filed Feb. 26, 2000, in the Korean Patent Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a circuit and a method to prevent errors in recording in an optical recording and/or reproducing apparatus, and more particularly, to a circuit and a method to prevent errors in recording in which recording is prohibited unless a rotation speed or a write rate of a recording medium is constant.
2. Description of the Related Art
For a recording format in a conventional disc such as a compact disc-recordable (CD-R), or a compact disc-rewritable (CD-RW), a constant linear velocity (CLV) method is adopted to extend data storage capacity. For a recording format in a conventional digital versatile disc-random access memory (DVD-RAM), a special zoned constant linear velocity (ZCLV) in which a constant angular velocity (CAV) method is used in a zone, while a CLV method is used between zones. Due to advancements in hardware, most compact disc-read only memories (CD-ROMs) achieve a high speed access by reproduction using a CAV method. In accordance with future developments in technology, it is expected that a DVD-RAM will be reproduced with a CAV method.
When data must be recorded with a constant rate CLV or ZLCV method, data is recorded immediately after the data is reproduced with the CAV method. A quantity of light is not sufficient to record data on the disc because the rotation speed of the disc does not reach a rotation speed of a motor at a constant recording rate. Therefore, the data cannot be recorded smoothly, and a high speed access cannot be achieved. Thus, reproduction of data is subject to errors. Particularly, in a CD-R, or a DVD-R, because of the occurrence of errors, data cannot be recorded, which is a disadvantage of the present design.
Furthermore, when data is recorded from a first area to a second area in a DVD-RAM which must use the ZCLV method, a physical identification (PID) that indicates a physical location on the disc is normally read. However, the rotation speed of the disc does not reach a rotation speed for a constant recording rate, thus the same problem exists regarding an insufficient quantity of light for recording data in the disc, and therefore data cannot be recorded smoothly.
Accordingly, it is an object of the present invention to provide a circuit to prevent errors in reproducing data caused by errors during recording, by prohibiting recording if a rotation speed of a disc is not at a desired constant rate when the data is recorded in an optical recording and/or reproducing apparatus at a constant rate, and the data is reproduced at a constant or a variable rate
It is another object to provide a method of preventing errors in a reproduction signal caused by writing errors during recording, by prohibiting recording if a rotation speed of a disc is not at a desired constant rate when data is recorded in an optical recording and/or reproducing apparatus at a constant rate, and in which the data is reproduced at a constant or a variable rate.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing objects of the present invention are achieved by providing a circuit to prevent errors in recording in an optical recording and/or reproducing apparatus in which data is recorded at a constant rate on a recording medium wobbled at a predetermined frequency, and the data is reproduced at a constant or a variable rate from the recording medium. The circuit has a first detector to generate a detection pulse by determining whether or not a counted value is in the permissible range of a constant write rate. The counted value is obtained by counting a number of cycles of an input wobble signal, using as a reference a system clock signal having frequencies higher than the predetermined frequency of the wobble signal. The circuit further comprises a second detector to generate a recording control signal to allow or to prohibit a record operation after determining whether the detection pulse meets a predetermined lock condition or a predetermined unlock condition.
The above objects of the present invention may also be achieved by providing a method of preventing errors in recording in an optical recording and/or reproducing apparatus in which data is recorded at a constant rate on a recording medium wobbled at a predetermined frequency, and the data can be reproduced at a constant or a variable rate from the recording medium. The method comprises generating a detection pulse by determining whether or not a counted value is in the permissible range of a constant write rate. The counted value is obtained by counting a number of cycles of an input wobble signal, using as a reference a system clock signal having frequencies higher than the predetermined frequency of the wobble signal. The method further comprises generating a recording control signal to allow or to prohibit a record operation after determining whether the detection pulse meets a predetermined lock condition or a predetermined unlock condition.